message remailed after list corrected

To: common-lisp@SU-AI.ARPA

Subject: message remailed after list corrected

From: Martin Frost <ME@SU-AI.ARPA>

Date: Sat, 17 Nov 1984 02:16:00 -0000

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Date: Fri, 16 Nov 1984 23:52:00 -0000
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From: Rob MacLachlan <RAM@CMU-CS-C.ARPA>
To: common-lisp@SU-AI.ARPA
Subject: Inconsistency in CLM
There is an inconsistency in the CLM in the definition of Ceiling,
Floor, Truncate and Round in the explanation of the meaning of the
second argument. It is not in general true that:
(op x y) <==> (op (/ x y))
Consider Truncate with X = 1 and Y = -3/2:
(/ 1 -3/2) => -2/3
(truncate -2/3) => 0, -2/3
This result violates the formula describing the relation between the
return values and the arguments:
(+ (* 0 1) -2/3) => -2/3 ; Not 1!
While the first value of the two expressions will be the same, the
remainder is often different.
Rob